window.onload = function () {
  document.addEventListener('touchstart', function (ev) {
    ev = ev || event
    ev.preventDefault()
  })

  // ;(function(){
  //   var styleNode = document.createElement('style')
  //   var w = document.documentElement.clientWidth / 16
  //   styleNode.innerHTML = 'html{font-size:'+ w +'px !important}'
  //   document.head.appendChild(styleNode)
  // })()

  ;(function (designWidth, maxWidth) {
    var doc = document,
      win = window;
    var docEl = doc.documentElement;
    var tid;
    var rootItem, rootStyle;

    function refreshRem() {
      var width = docEl.getBoundingClientRect().width;
      if (!maxWidth) {
        maxWidth = 540;
      };
      if (width > maxWidth) {
        width = maxWidth;
      }
      //与淘宝做法不同，直接采用简单的rem换算方法1rem=100px
      var rem = width * 100 / designWidth;
      //兼容UC开始
      rootStyle = "html{font-size:" + rem + 'px !important}';
      rootItem = document.getElementById('rootsize') || document.createElement("style");
      if (!document.getElementById('rootsize')) {
        document.getElementsByTagName("head")[0].appendChild(rootItem);
        rootItem.id = 'rootsize';
      }
      if (rootItem.styleSheet) {
        rootItem.styleSheet.disabled || (rootItem.styleSheet.cssText = rootStyle)
      } else {
        try {
          rootItem.innerHTML = rootStyle
        } catch (f) {
          rootItem.innerText = rootStyle
        }
      }
      //兼容UC结束
      docEl.style.fontSize = rem + "px";
    };
    refreshRem();

    win.addEventListener("resize", function () {
      clearTimeout(tid); //防止执行两次
      tid = setTimeout(refreshRem, 300);
    }, false);

    win.addEventListener("pageshow", function (e) {
      if (e.persisted) { // 浏览器后退的时候重新计算
        clearTimeout(tid);
        tid = setTimeout(refreshRem, 300);
      }
    }, false);

    if (doc.readyState === "complete") {
      doc.body.style.fontSize = "16px";
    } else {
      doc.addEventListener("DOMContentLoaded", function (e) {
        doc.body.style.fontSize = "16px";
      }, false);
    }
  })(375, 750);
}
